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Biomedical subjects

S Katsuda

Publications and source records attributed to S Katsuda.

104 records · Page 6Linked to original sources
PubMed1983

Overall open-loop gain of rapidly acting arterial pressure control system in rabbits.

We estimated the overall open-loop gain of the rapidly acting arterial pressure control system without surgically or pharmacologically opening the reflex loop in rabbits. Animals anesthetized by intravenous injection of Nembutal (27.5 mg X kg-1 body weight) and heparinized were bled by 2 ml X kg-1 body weight within 1-2 s through a catheter inserted into the aortic arch. Arterial pressure change after the quick mild hemorrhage was monitored via a catheter placed in the right subclavian artery for more than 2 min. The overall open-loop gain of the lumped arterial pressure control system determined from the mean arterial pressure response to the hemorrhage was 7.3. It was almost constant over the range between 12.9 and 22.2 kPa systemic pressure.

Animals↗
PubMed1983

Diagnostic aspect of spindle-cell sarcomas by electron microscopy.

Spindle-cell sarcomas in the somatic soft tissue and soft parts, including fibrosarcoma, leiomyosarcoma, malignant fibrous histiocytoma (MFH), and malignant schwannoma were examined by electron microscopy in order to delineate the most reliable cellular features for their diagnosis. Fibrosarcoma consisted largely of fibroblastic cells and leiomyosarcoma cells were packed in forming small cell groups with constant junctional complexes of nexus and zonula adherens types. MFH showed variable cellular features containing the cells with myofibroblastic and histiocytic differentiation. Malignant schwannoma was characterized by tumor cells having slender cytoplasmic processes with overlapping or interdigitation and thick basement membrane. These ultrastructural features were contributory to the differential diagnosis of the sarcomas examined.

Adult↗
PubMed1980

Two siblings with hypophosphatasia.

Two siblings with hypophosphatasia, one of whom was autopsied, were reported. The first case which was a product of a 26-year-old mother complicated by hydroamnios represented poor mineralization of the entire bones on X-ray examination and died shortly after birth. The second case weighing 1850 g delivered from the same mother had a rhizomelic micromelia and poor visualization of the skull, long bones and vertebral bones on X-ray at postmortem. The autopsy on the second case showed small thoracic cage with rachitic rosaries of ribs, membranous skull and poorly ossified vertebral and long bones. Microscopically, there was a marked disturbance of both enchondral and membranous ossifications similar to the histology of rachitis. A biochemical examination showed low alkaline phosphatase, high calcium and normal PTH in the serum. Further examination of their family revealed relatively low level of alkaline phosphatase of the parents and one of their brothers which suggsted they were carriers of hypophosphastasia. Previous reports on hypophosphatasia were reviewed and differential diagnosis of hypophosphatasia from the other congenital dwarfisms was discussed.

Adult↗
PubMedDate not supplied

Dose- and treatment duration-related effects of p-tert-octylphenol on female rats.

We conducted a study to investigate the relation between estrogenic effects of p-tert-octylphenol (OP) and serum concentration as well as treatment duration. Adult ovariectomized rats were given daily subcutaneous injections of OP for 2 and 14 days. 17beta-Estradiol was also administrated at a dose of 5 microg/kg. OP was detected in serum at doses of 25 mg/kg and above for 2 days and with multiple doses (14 days) of 12.5 mg/kg. Uterine weights and luminal epithelial height were increased although the effects were weak compared to 17beta-estradiol. Estrous conversion of the vaginal smear was detected only in 14-day-treated animals. OP-treatment for 2 days caused a dose-related increase in proliferation of uterine luminal, glandular, and stromal cells and vaginal epithelial cells. From the 14-day experiment, the minimum estrogenic dose level of OP was concluded to be 25 mg/kg/day and the serum level at the dose was determined to be about 80 ng/ml. These findings demonstrated that OP exerts estrogenic activity in the female reproductive tract of ovariectomized rats only at high levels of exposure and that the effects are fundamentally related to serum OP levels.

Animals↗
PubMedDate not supplied

Electron microscopic and immunoelectron microscopic demonstration of pancreatic polypeptide cells in glucagonoma: colocalization of pancreatic peptide and glucagon in single secretory granules.

We describe a case of pancreatic tumor in a 65-year-old woman with typical glucagonoma syndrome. Plasma glucagon (GL) and pancreatic polypeptide (PP) were markedly elevated up to 1404 and 1200 pg/ml, respectively. Histologic examination of the metastatic tumors in liver and lymph nodes showed endocrine-type tumors composed of GL-positive cells some of which coexpressed PP immunoreactivity. Electron microscopy revealed the tumor cells with single-type secretory granules similar to normal A cell granules. Double immunogold staining demonstrated both GL and PP immunoreactivities in the same secretory granules. Biologic and diagnostic significance of coexpression of PP and GL in a single secretory granules of pancreatic endocrine tumors is discussed briefly.

Adenoma, Islet Cell↗
PubMedDate not supplied

Pathological study of implanted dacron grafts in surgery of thoracic aortic aneurysms.

We studied woven dacron grafts that had been implanted in 5 patients of thoracic aortic aneurysms. In addition to usual stains, immunocytochemical analysis was performed using monoclonal antibodies to the muscle actin (HHF35) and to the macrophage (HAM56). In the graft of 5 and 24 days implantation, thin thrombi containing red cells and fibrin covered the luminal surface in some places, and macrophages came into the thrombi. In the grafts of 12 and 38 months implantation, intimal hyperplasia of 0.2-1.0 mm thickness was seen at the anastomotic segments with the accumulation of smooth muscle cells. Except for the anastomotic segments, connective tissue matrix with collagen fibers covered the luminal surface, and in some hollows of the graft crimps, old and fresh thombi were seen in layers. Organizing thrombi of 1.0 mm thickness attached where the branched graft was anastomosed to the main graft. Anastomotic intimal hyperplasia in the graft of 148 month implantation was 0.4-1.0 mm in thickness and 5-10 mm in length, and aside from the intimal hyperplasia, an endothelial lining did not cover the luminal surface of the graft. In the thoracic aorta, woven dacron graft implantation did not cause a critical stenosis with the intimal hyperplasia. The mural thrombi formed at the branched graft, however, threatened to result in graft occlusion or embolization.

Aortic Aneurysm, Thoracic↗